Super Mario Galaxy[a][b] is a 2007 platform action-adventure video game developed and published by Nintendo for the Wii. It is the third 3D game in the Super Mario series. As Mario or Luigi, the player embarks on a quest to rescue Princess Peach, save the universe from Bowser, and collect 121 Power Stars. The levels in the game consist of galaxies filled with minor planets and worlds, with different variations of gravity, the central element of gameplay. The player character is controlled using the Wii Remote and Nunchuk, and completes missions, fights bosses, and reaches certain areas to collect Power Stars. Certain levels use the motion-based Wii Remote functions.